Prior art methods of measuring displaceable material, such conveyed crushed rock, coal, feed, etc, augered material such as powder, seeds, cement, etc, and liquid material such as water, oil, etc, are limited to conveyor belt and gravimetric scales which are calibrated to read in unit weight per unit time, or liquid flow rate meters reading in units of liquid measure per unit time, etc. The prior art methods strive for accuracy through sophisticated electronic components in precision electro-mechanical interaction, such as conveyor scales with electronic load cells, sensing physical movement in relation to the amount of material on the conveyor scale, or rotary impellers coupled to a sensor for liquids, or electronic physical displacement sensors mechanically coupled to an impacting surface measuring the rate of material flowing through a pipe, etc, resulting in the desired unit of measurement.
Prior art conveyor belt scales typically consists of a scale carriage with load cells and/or linear differential transformers and associated electronic circuits, a conveyor motion or speed sensor, and several idlers before and after the scale carriage. Installation of a conveyor belt scale generally requires mechanics and welders to mount the scale to the conveyor frame, electrician to run conduit and wires from the main panel in the control room to the scale, and trained factory technicians to inspect and configure the scale to the specific application. Thus, the installation process can be quite involved, including significant installation work, lengthy field wire runs conveyor, frame modification, weigh bridge installation, mechanical line-up for accuracy, additional sensor mounting and associated wires for conveyor speed, etc.
Conventional belt scales require almost constant calibration and trimming to account for variations in material density, conveyor belt carriage alignment, conveyor belt centering, wedged rocks in-between the scale measuring beams, etc., to obtain material flow rate data within the error tolerance of the scales. Maintenance personnel would need basic understanding of the conveyor belt system, scale carriage, load cell, speed sensor, electronics associated, etc., in addition to being familiar with voluminous user manuals. Thus, prior art systems are sophisticated electro-mechanical systems requiring highly trained personnel for installation and maintenance.
There is therefore a need for flow rate monitor that replaces complicated belt scales and requires no expertise on conveyor scales and their associated load cells, linear voltage differential transformers, scale beams, etc. and minimizes a large portion of the installation headaches that generally accompany the industrial belt scales.
There is therefore a need for flow rate monitor that compensated for the zero drift caused by mechanical components warm-up, changes in the ambient temperature and seasonal changes.